An optimized adaptive spike detector for behavioural experiments

Bengali has a robust medial geminate/singleton contrast across oral stops and nasals in five places of articulation. This chapter presents a synchronic account of the phonological system involving the consonantal length contrast, which supports an asymmetric moraic representation of geminates. Based on these representational assumptions, two EEG and two behavioural experiments were conducted to investigate the processing of this geminate/singleton contrast by Bengali native speakers. The results reveal a processing asymmetry for the duration contrast: the processing of the duration contrast is indeed asymmetric: a geminate mispronunciation is accepted for a singleton real word, while the reverse is not the case. This provides evidence that the lexical representation of the duration contrast must be asymmetric and thus privative rather than equipollent.

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In search of the spectral composition of an effective light trap for the mushroom pest Lycoriella ingenua (Diptera: Sciaridae)

Scientific Reports ◽

10.1038/s41598-021-92230-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sándor Kecskeméti ◽

András Geösel ◽

József Fail ◽

Ádám Egri

Keyword(s):

Light Intensity ◽

Spectral Sensitivity ◽

Fungal Pathogens ◽

Light Trap ◽

Spectral Composition ◽

Wavelength Dependence ◽

Crop Damage ◽

Photon Flux ◽

Compound Eyes ◽

Behavioural Experiments

AbstractCertain fungus gnats, like Lycoriella ingenua are notorious pests in agriculture, especially in mushroom production. While larvae cause mainly direct crop damage, adults are vectors of several dangerous fungal pathogens. To promote the development of pesticide-free management methods, such as light trapping, we measured the spectral sensitivity of L. ingenua compound eyes with electroretinography and performed two different behavioural experiments to reveal the wavelength dependence of phototaxis in this species. The spectral sensitivity of the compound eyes is bimodal with peaks at 370 nm (UV) and 526 nm (green). Behavioural experiments showed that attraction to light as a function of wavelength depends on light intensity. In our first experiment, where the minimal photon flux (105–109 photons/cm2/s) needed for eliciting a phototactic response was determined wavelength by wavelength, phototaxis was strongest in the green spectral range (~526 nm). In the other behavioural experiment, where wavelength preference was tested under a higher but constant light intensity (~1013 photons/cm2/s), the highest attraction was elicited by UV wavelengths (398 nm). Our results suggest that both UV and green are important spectral regions for L. ingenua thus we recommend to use both UV (~370-398 nm) and green (~526 nm) for trapping these insects.

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Effects of a commercially formulated glyphosate solutions at recommended concentrations on honeybee (Apis mellifera L.) behaviours

Scientific Reports ◽

10.1038/s41598-020-80445-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Qi-Hua Luo ◽

Jing Gao ◽

Yi Guo ◽

Chang Liu ◽

Yu-Zhen Ma ◽

...

Keyword(s):

Apis Mellifera ◽

Theoretical Basis ◽

Chronic Toxicity ◽

Sublethal Effects ◽

Significant Decline ◽

Learning Ability ◽

Notification System ◽

Climbing Ability ◽

Behavioural Experiments ◽

Sucrose Responsiveness

AbstractGlyphosate, the active ingredient of the most widely used commercial herbicide formulation, is extensively used and produced in China. Previous studies have reported sublethal effects of glyphosate on honeybees. However, the effects of commercially formulated glyphosate (CFG) at the recommended concentration (RC) on the chronic toxicity of honeybees, especially on their behaviours, remain unknown. In this study, a series of behavioural experiments were conducted to investigate the effects of CFG on honeybees. The results showed that there was a significant decline in water responsiveness at 1/2 × , 1 × and 2 × the RC after 3 h of exposure to CFG for 11 days. The CFG significantly reduced sucrose responsiveness at 1/2 × and 1 × the RC. In addition, CFG significantly affected olfactory learning ability at 1/2 × , 1 × , and 2 × the RC and negatively affected memory ability at 1/2 × and 1 × the RC. The climbing ability of honeybees also significantly decreased at 1/2 × , 1 × and 2 × the RC. Our findings indicated that, after they were chronically exposed to CFG at the RC, honeybees exhibited behavioural changes. These results provide a theoretical basis for regulating field applications of CFG, which is necessary for establishing an early warning and notification system and for protecting honeybees.

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Olfactory Stimuli and Oviposition in the Blowfly, Phormia Regina Meigen

Journal of Experimental Biology ◽

10.1242/jeb.39.4.603 ◽

1962 ◽

Vol 39 (4) ◽

pp. 603-615

Author(s):

D. I. WALLIS

Keyword(s):

Olfactory Receptors ◽

Phormia Regina ◽

Minor Role ◽

Egg Distribution ◽

Tactile Stimuli ◽

Olfactory Stimuli ◽

Behavioural Experiments ◽

A Minor ◽

Sensory Mechanisms

1. The work described attempts to elucidate the sensory mechanisms involved in the act of oviposition. 2. A brief account of the morphology of the ovipositor and the distribution of the various sensilla on it is given. 3. Behavioural experiments have shown unequivocally that receptors on the anal leaflets of the ovipositor are olfactory and can mediate oviposition. Flies are able to discriminate when antennal, palp and labellar receptors are blocked, but not when the ovipositor pegs are waxed over as well. A method for waxing the latter is described. 4. Sensilla on the antennae, labellum and ovipositor perceive the olfactory stimuli which are important in inducing oviposition. Possibly there are olfactory receptors at other sites which mediate other types of behaviour. 5. Tactile stimuli perceived mainly through sensilla on the ovipositor can play an important role in egg distribution and a minor role, possibly, in inducing oviposition. 6. All the evidence suggests the pegs are the olfactory receptors on the ovipositor which mediate oviposition. 7. A summary of factors known or suspected to influence oviposition is given.

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Stabilizing selection on individual pattern elements of aposematic signals

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.0926 ◽

2017 ◽

Vol 284 (1861) ◽

pp. 20170926 ◽

Cited By ~ 17

Author(s):

Anne E. Winters ◽

Naomi F. Green ◽

Nerida G. Wilson ◽

Martin J. How ◽

Mary J. Garson ◽

...

Keyword(s):

Pattern Analysis ◽

Marine Organism ◽

Warning Signal ◽

Colour Pattern ◽

Stabilizing Selection ◽

Warning Signals ◽

Fish Predator ◽

Selection For ◽

Aposematic Signals ◽

Behavioural Experiments

Warning signal variation is ubiquitous but paradoxical: low variability should aid recognition and learning by predators. However, spatial variability in the direction and strength of selection for individual elements of the warning signal may allow phenotypic variation for some components, but not others. Variation in selection may occur if predators only learn particular colour pattern components rather than the entire signal. Here, we used a nudibranch mollusc, Goniobranchus splendidus , which exhibits a conspicuous red spot/white body/yellow rim colour pattern, to test this hypothesis. We first demonstrated that secondary metabolites stored within the nudibranch were unpalatable to a marine organism. Using pattern analysis, we demonstrated that the yellow rim remained invariable within and between populations; however, red spots varied significantly in both colour and pattern. In behavioural experiments, a potential fish predator, Rhinecanthus aculeatus , used the presence of the yellow rims to recognize and avoid warning signals. Yellow rims remained stable in the presence of high genetic divergence among populations. We therefore suggest that how predators learn warning signals may cause stabilizing selection on individual colour pattern elements, and will thus have important implications on the evolution of warning signals.

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Odour of domestic dogs infected with Leishmania infantum is attractive to female but not male sand flies: Evidence for parasite manipulation

PLoS Pathogens ◽

10.1371/journal.ppat.1009354 ◽

2021 ◽

Vol 17 (3) ◽

pp. e1009354

Author(s):

Monica E. Staniek ◽

James G. C. Hamilton

Keyword(s):

Leishmania Infantum ◽

Etiologic Agent ◽

Human Infection ◽

T Test ◽

Sand Fly ◽

Lutzomyia Longipalpis ◽

Sand Flies ◽

Control Female ◽

Behavioural Experiments ◽

Paired T Test

Globally visceral leishmaniasis (VL) causes thousands of human deaths every year. In South America, the etiologic agent, Leishmania infantum, is transmitted from an infected canine reservoir to human hosts by the bite of the sand fly vector; predominantly Lutzomyia longipalpis. Previous evidence from model rodent systems have suggested that the odour of infected hosts is altered by the parasite making them more attractive to the vector leading to an increased biting rate and improved transmission prospects for the pathogen. However, there has been no assessment of the effect of Le infantum infection on the attractiveness of dogs, which are the natural reservoirs for human infection. Hair collected from infected and uninfected dogs residing in a VL endemic city in Brazil was entrained to collect the volatile chemical odours present in the headspace. Female and male Lu. longipalpis sand flies were offered a choice of odour entrained from infected and uninfected dogs in a series of behavioural experiments. Odour of uninfected dogs was equally attractive to male or female Lu. longipalpis when compared to a solvent control. Female Lu. longipalpis were significantly more attracted to infected dog odour than uninfected dog odour in all 15 experimental replicates (average 45.7±0.87 females attracted to infected odour; 23.9±0.82 to uninfected odour; paired T-test, P = 0.000). Male Lu. longipalpis did not significantly prefer either infected or uninfected odour (average 36.1±0.4 males to infected odour; 35.7±0.6 to uninfected odour; paired T-test, P = 0.722). A significantly greater proportion of females chose the infected dog odour compared to the males (paired T-test, P = 0.000). The results showed that the odour of dogs infected with Le. infantum was significantly more attractive to blood-seeking female sand flies than it was to male sand flies. This is strong evidence for parasite manipulation of the host odour in a natural transmission system and indicates that infected dogs may have a disproportionate significance in maintaining infection in the canine and human population.

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Impact of a Vibrotactile Belt on Emotionally Challenging Everyday Situations of the Blind

Sensors ◽

10.3390/s21217384 ◽

2021 ◽

Vol 21 (21) ◽

pp. 7384

Author(s):

Charlotte Brandebusemeyer ◽

Anna Ricarda Luther ◽

Sabine U. König ◽

Peter König ◽

Silke M. Kärcher

Keyword(s):

Emotional Impact ◽

Vibrotactile Stimulation ◽

Angular Rotation ◽

Straight Line ◽

Before And After ◽

Fixed Reference ◽

Behavioural Experiments ◽

Triangle Completion ◽

Subjective Discomfort ◽

Magnetic North

Spatial orientation and navigation depend primarily on vision. Blind people lack this critical source of information. To facilitate wayfinding and to increase the feeling of safety for these people, the “feelSpace belt” was developed. The belt signals magnetic north as a fixed reference frame via vibrotactile stimulation. This study investigates the effect of the belt on typical orientation and navigation tasks and evaluates the emotional impact. Eleven blind subjects wore the belt daily for seven weeks. Before, during and after the study period, they filled in questionnaires to document their experiences. A small sub-group of the subjects took part in behavioural experiments before and after four weeks of training, i.e., a straight-line walking task to evaluate the belt’s effect on keeping a straight heading, an angular rotation task to examine effects on egocentric orientation, and a triangle completion navigation task to test the ability to take shortcuts. The belt reduced subjective discomfort and increased confidence during navigation. Additionally, the participants felt safer wearing the belt in various outdoor situations. Furthermore, the behavioural tasks point towards an intuitive comprehension of the belt. Altogether, the blind participants benefited from the vibrotactile belt as an assistive technology in challenging everyday situations.

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Fear-specific leftward bias in gaze direction judgment

Scientific Reports ◽

10.1038/s41598-021-97039-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yue Zhang ◽

Qiqi Hu ◽

Xinwei Lai ◽

Zhonghua Hu ◽

Shan Gao

Keyword(s):

Judgment Task ◽

Gaze Direction ◽

Emotional Information ◽

Cerebral Lateralization ◽

Low Level ◽

The Gaze ◽

Fearful Faces ◽

Perception Bias ◽

Behavioural Experiments ◽

Direction Judgment

AbstractPrevious studies have shown that humans have a left spatial attention bias in cognition and behaviour. However, whether there exists a leftward perception bias of gaze direction has not been investigated. To address this gap, we conducted three behavioural experiments using a forced-choice gaze direction judgment task. The point of subjective equality (PSE) was employed to measure whether there was a leftward perception bias of gaze direction, and if there was, whether this bias was modulated by face emotion. The results of experiment 1 showed that the PSE of fearful faces was significantly positive as compared to zero and this effect was not found in angry, happy, and neutral faces, indicating that participants were more likely to judge the gaze direction of fearful faces as directed to their left-side space, namely a leftward perception bias. With the response keys counterbalanced between participants, experiment 2a replicated the findings in experiment 1. To further investigate whether the gaze direction perception variation was contributed by emotional or low-level features of faces, experiment 2b and 3 used inverted faces and inverted eyes, respectively. The results revealed similar leftward perception biases of gaze direction in all types of faces, indicating that gaze direction perception was biased by emotional information in faces rather than low-level facial features. Overall, our study demonstrates that there a fear-specific leftward perception bias in processing gaze direction. These findings shed new light on the cerebral lateralization in humans.

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Behavioural evidence for self-medication in bumblebees?

F1000Research ◽

10.12688/f1000research.6262.3 ◽

2015 ◽

Vol 4 ◽

pp. 73 ◽

Cited By ~ 32

Author(s):

David Baracchi ◽

Mark J. F. Brown ◽

Lars Chittka

Keyword(s):

Secondary Metabolites ◽

Sucrose Solution ◽

Parasite Load ◽

Foraging Activity ◽

Self Medication ◽

Crithidia Bombi ◽

Nicotine Consumption ◽

Behavioural Experiments ◽

Behavioural Tests ◽

Behavioural Evidence

The presence of antimicrobial secondary metabolites in nectar suggests that pollinators, which are threatened globally by emergent disease, may benefit from the consumption of nectars rich in these metabolites. We tested whether nicotine, a nectar secondary metabolite common in Solanaceae and Tilia species, is used by parasitized bumblebees as a source of self-medication, using a series of toxicological, microbiological and behavioural experiments. Caged bees infected with Crithidia bombi had a slight preference for sucrose solution laced with the alkaloid and behavioural tests showed that the parasite infection induced an increased consumption of nicotine during foraging activity, though nicotine had an appetite-reducing effect overall. When ingested, nicotine delayed the progression of a gut infection in bumblebees by a few days, but dietary nicotine did not clear the infection, and after 10 days the parasite load approached that of control bees. Moreover, when pathogens were exposed to the alkaloid prior to host ingestion, the protozoan’s viability was not directly affected, suggesting that anti-parasite effects were relatively weak. Nicotine consumption in a single dose did not impose any cost even in starved bees but the alkaloid had detrimental effects on healthy bees if consistently consumed for weeks. These toxic effects disappeared in infected bees, suggesting that detoxification costs might have been counterbalanced by the advantages in slowing the progression of the infection. Nicotine consumption did not affect bee lifespan but the reduction in the parasite load may have other likely unexplored subtle benefits both for individual bees and their colony. Potential evidence for self-medication is discussed. The contention that secondary metabolites in nectar may be under selection from pollinators, or used by plants to enhance their own reproductive success, remains to be confirmed.

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Continuous Magnitude Production of Loudness

Frontiers in Psychology ◽

10.3389/fpsyg.2021.635557 ◽

2021 ◽

Vol 12 ◽

Author(s):

Josef Schlittenlacher ◽

Wolfgang Ellermeier

Keyword(s):

Power Law ◽

Line Length ◽

Time Varying ◽

Magnitude Production ◽

Consistency Check ◽

Regression Effects ◽

Systematic Biases ◽

Behavioural Experiments ◽

The Given ◽

Stevens’S Power Law

Continuous magnitude estimation and continuous cross-modality matching with line length can efficiently track the momentary loudness of time-varying sounds in behavioural experiments. These methods are known to be prone to systematic biases but may be checked for consistency using their counterpart, magnitude production. Thus, in Experiment 1, we performed such an evaluation for time-varying sounds. Twenty participants produced continuous cross-modality matches to assess the momentary loudness of fourteen songs by continuously adjusting the length of a line. In Experiment 2, the resulting temporal line length profile for each excerpt was played back like a video together with the given song and participants were asked to continuously adjust the volume to match the momentary line length. The recorded temporal line length profile, however, was manipulated for segments with durations between 7 to 12 s by eight factors between 0.5 and 2, corresponding to expected differences in adjusted level of −10, −6, −3, −1, 1, 3, 6, and 10 dB according to Stevens’s power law for loudness. The average adjustments 5 s after the onset of the change were −3.3, −2.4, −1.0, −0.2, 0.2, 1.4, 2.4, and 4.4 dB. Smaller adjustments than predicted by the power law are in line with magnitude-production results by Stevens and co-workers due to “regression effects.” Continuous cross-modality matches of line length turned out to be consistent with current loudness models, and by passing the consistency check with cross-modal productions, demonstrate that the method is suited to track the momentary loudness of time-varying sounds.

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